$74k quoted for power connection -- Off Grid seemed like a good idea but Nah!

This afternoon we received a letter from Top Energy which we have been eagerly awaiting for the past 6 weeks. It contained the quotation for a power connection to our new house site:

• $12,128 for capital contribution towards installing new 15kVA transformer
• $53,354 for installation of 750 metres of overhead 11kV line (a helicopter job)
• $8,208 to install 230 metres of 240V underground cable in a trench to be provided by us
• TOTAL $73,690 + trenching/burying cost

Aye, aye, aye that about blew us away [:0] [:0] [:0] [:0] [:0] [:0] [:0] [:0] [:0] [:0]

Keeping in mind the cost that others (including Kate) have paid for their off-grid systems, we had decided that if the quote came in at more than $50k, we would bite the bullet and go off-grid.

So, it looks like that is what we will be doing...

In trying to get my head around it all, there are a couple of things I would like suggestions on how to tackle:

- Water pumping: Our new house site is the highest point on the property, so we cannot gravity feed. Water will be pumped to a nearby 15,000L tank using a solar pump at our dam. But we need to have adequate pressure for showers etc, and that means having a reasonably powerful pump.

Is it viable to run a normal AC mains constant pressure pump (like Grundfos) off an inverter supply?

Or is some other type of pump better suited which has less starting current?

- Batteries: Approximately how many years would a good quality set of deep cycle batteries last before they need replacing?

How much would a typical set of deep cycle batteries cost?

Thanks to anyone who can point me in the right direction.

Hi Grant...welcome to the club

The best thing to do is to speak to Darren at thewattshop He's very helpful and can talk you through it all. The battery life depends on what capacity (is that the right term?) and how well you look after them [}]

Good news is that solar panels are getting cheaper all the time...

Cheers
Kate

Thanks Kate. I remembered that you had mentioned The Watt Shop and have spent the last hour or so reading all Darren's FAQs. Some really good info. there but it didn't directly cover most of the points I mentioned.

However, Darren did say that he had been using the same set of batteries for 8 years, and they were still going strong, so that is much more than the 5 or so years I was expecting.

About ten years ago some friends got quoted $30k to connect to the grid. They built a primitive but adequate wind and solar system for $10k. If the battery bank gets low under high use they leave the diesel car idling and charge the battery bank off its alternator.

EEEEEEEEEKKKKKK. I hope you were sitting down when that letter arrived. IF you set up a load of bicycles or a round washing line, and tie a goat and a sheep and the dog to the arms of the rotator, so that they run around surely that would vitalise the power store batteries, and any visitors have to do 15min on the bike,before they can have that cup of coffee.

Scary numbers.

The first thing to do is decide exactly what you can live with regarding the power supply. If you think it would be annoying to have to severely restrict your computer (LSB forum ) time, your use of washing machine, vacuum cleaner etc. make that call at the start, and say the system must cope with these demands. This will mean you don't end up pricing a system that won't suit.

Do you have appliances that require pure sine wave? (Probably. Many electronics do.) If so your inverter will need to produce this.

Write down how much current all your electrical things draw, and what time period they run for. Fridges and freezers and pumps and septic systems tend to be rather greedy when looked at over the whole year.

For example, one of the greediest things (for short term current draw) we will be running on our system is the welder, so that determined the maximum current. But, because it is a short term user of power, we can use the generator to boost the output, when required, through a very clever (and expensive) inverter which doubles the system capacity short term, by allowing a draw from the batteries and the generator at the same time.

GrantK;318388 wrote: Do you mind me asking how much your battery bank cost?

I've pm'd you

Go with heavy duty lead acid batteries ie as used in a forklift, a large bank of 24 or 48 volt. You need to work out your power consumption needs and work backwards to see what size battery bank you require. I had a 600 amp hour battery bank that fully charged would last 2 days. My generator then auto started and charged in less than 3 hours through powerful invertor/charger. 2nd hand batteries can be sourced very reasonable from Forklift hire places and will have many years life left in them.

My bank ran a modest 2 bedroom home, commercial chiller and energy effecient appliances. You need to be energy concious ie when the genertor is running operate heavy drain appliances such as washing machines and water pumps. Have things like you fridge/freezer on timers comming on say twice a day for an hour or so (depends on how often you open the door). Use energy light bulbs. Solar panels/wind turbine will extend the time between generator operating. Better still if you have a creek with a good flow investigate a water turbine.

I would think that to operate a modest 3-4 bedroom house would cost 30-40k. This would include battery bank, generator, invertor/charger, wind turbine, cable and instal. DO NOT BE TALKED INTO USING ANYTHING CHINESE.

Like wise stay away from ex telecom/gel batteries, they do not like constant heavy discharging/recharging.

SEEK PROFFESIONAL ADVICE!! and insist on speaking to previous clients of who ever you use.

Thanks very much everyone for your suggestions and comments. I got diverted into doing a bit of early spring cleaning, even though it's not spring yet... Bit of a worry eh :confused:

Hawkspur;318397 wrote: Scary numbers.

The first thing to do is decide exactly what you can live with regarding the power supply. If you think it would be annoying to have to severely restrict your computer (LSB forum ) time, your use of washing machine, vacuum cleaner etc. make that call at the start, and say the system must cope with these demands. This will mean you don't end up pricing a system that won't suit.

Do you have appliances that require pure sine wave? (Probably. Many electronics do.) If so your inverter will need to produce this.

Write down how much current all your electrical things draw, and what time period they run for. Fridges and freezers and pumps and septic systems tend to be rather greedy when looked at over the whole year.

I have had a good look at the FAQs on here:

www.wattshop.co.nz/index.htm

And Darren suggests 3kWh per day, including a goodly amount of TV watching, which we generally don't do. Probably make up for it though with computer use [8D]

I will try and come up with some more accurate numbers for our situation. One saving grace is that we can leave the large (and power-hungry) chest deep freezers in the old house where they are at present, happily running away on mains power. We will just have a small/power efficient chest freezer in the new house, which can be stocked up every so often by going "shopping" at the old house

Hawkspur;318397 wrote: For example, one of the greediest things (for short term current draw) we will be running on our system is the welder, so that determined the maximum current. But, because it is a short term user of power, we can use the generator to boost the output, when required, through a very clever (and expensive) inverter which doubles the system capacity short term, by allowing a draw from the batteries and the generator at the same time.

I already have a grunty "Robin" (Subaru) 6.5kVA generator in my workshop for doing just that. It runs my welder with ease, as well as grinders, cut-off saws etc. Connection cost for the workshop would have been $10k, so I decided to buy a generator for $2300 instead. Definitely not a Chinese one though [xx(]

Kate;318399 wrote: I've pm'd you

Thank you Kate -- that was very helpful and enlightening. After seeing the figures, I am more convinced than ever that going Off-Grid is the way to go [8D]

cantyguy;318410 wrote: Go with heavy duty lead acid batteries ie as used in a forklift, a large bank of 24 or 48 volt. You need to work out your power consumption needs and work backwards to see what size battery bank you require. I had a 600 amp hour battery bank that fully charged would last 2 days. My generator then auto started and charged in less than 3 hours through powerful invertor/charger. 2nd hand batteries can be sourced very reasonable from Forklift hire places and will have many years life left in them.

Interesting tip, thanks CG, I will look into it.

cantyguy;318410 wrote: My bank ran a modest 2 bedroom home, commercial chiller and energy effecient appliances. You need to be energy concious ie when the genertor is running operate heavy drain appliances such as washing machines and water pumps.

So I take it that we can use a normal water pump, but just be careful how long it is running for?

cantyguy;318410 wrote: I would think that to operate a modest 3-4 bedroom house would cost 30-40k. This would include battery bank, generator, invertor/charger, wind turbine, cable and instal. DO NOT BE TALKED INTO USING ANYTHING CHINESE.

Definitely nothing Chinese here!

$30 - $40k sounds in line with other figures I have been given. Probably I would allow $50k to be on the safe side, and hopefully save some $ by doing the installation myself.

cantyguy;318410 wrote: SEEK PROFFESIONAL ADVICE!! and insist on speaking to previous clients of who ever you use.

Darren from The Watt Shop (as used by Kate) seems like a good first port of call. I have other alternatives collected from various A&P shows / Fieldays over recent years.

Thanks once again to everybody who responded.

I was recommended to use Darren by a previous client of his, since moving up to Northland we've met another couple he worked for who would also recommend him...

I had some readers in Northland who also chose to go off-grid, after working out anything over $40,000 to hook up to the grid wasn't worth it.

The husband wrote an interesting story about it, so I will email it to Inger shortly (since I don't know your email!)

Pumpkingirl;318467 wrote: The husband wrote an interesting story about it, so I will email it to Inger shortly (since I don't know your email!)

Thanks very much PG, I'll look forward to it

BTW, my e-mail address is the same as Inger's but with the inger@ replaced by grant@

We try to keep things simple where possible

Just emailed it to you both

The more relevant details are nearer the bottom, that outlines their system.

The first bit is still interesting though, if you wish to keep a happy marriage apparently

Hawkspur We bought an older welder/generater on a trailer to make life easier to fix things where they break also to go off grid we would have no problems with power as they use a lot:)

Pumpkingirl;318475 wrote: Just emailed it to you both

A most interesting read PG, and the technical details in that story are very helpful to us right now. Thanks again